[mactec54]

so far bought a spindle motor and the axis stepper drivers. Its not inverter duty but Im going to try it, since its larger HP my hope is it will not have temp issues. Have the VFD identified but its common so no hurry. Im going to Ebay the Emco drivers to raise money for the retrofit, I also have the transformer to sell. Im modelling the control to fit in a commercial wall cabinet, should have pics soon of the 3D models.
Attachment 314600

You don't need to change the Pulley with this motor, you will need the 5hp for your machining, this motor will do the 6,000 Rpm you need by just using your VFD programing

[CincyTJ]

You don't need to change the Pulley with this motor, you will need the 5hp for your machining, this motor will do the 6,000 Rpm you need by just using your VFD programing

thats great thanx, I wasnt sure if I could overdrive it 100% without heat issues. Likely I wouldnt be using the 6000RPM for 99% of the stuff I want to do anyway, but I do have some small aluminum parts and would like the capability. Do you think the continuous duty ather than inverter duty will have an issue? Finding a metric 100 frame and 3-5hp and inverter duty proved frustrating at best. I imagine in Europe it would have been much easier but the pickings are slim in US.

[mactec54]

thats great thanx, I wasnt sure if I could overdrive it 100% without heat issues. Likely I wouldnt be using the 6000RPM for 99% of the stuff I want to do anyway, but I do have some small aluminum parts and would like the capability. Do you think the continuous duty ather than inverter duty will have an issue? Finding a metric 100 frame and 3-5hp and inverter duty proved frustrating at best. I imagine in Europe it would have been much easier but the pickings are slim in US.

Baldor Washdown motors are rated to 6,000 in there spec's, I have run them at 8,000 if you get one get it with the Rotor Grounding Brush already mounted, you will have a much better Bearing life, this is something to add to your VFD driven motor, or any for that matter

[CincyTJ]

I already have the motor, is there something off the shelf I can add or do I need to design a custom shaft ground? I saw this in another Emco120 retrofit build and didnt know what it was.

[mactec54]

I already have the motor, is there something off the shelf I can add or do I need to design a custom shaft ground? I saw this in another Emco120 retrofit build and didnt know what it was.

It's not an Emco thing, it is what should be done for any VFD driven AC motor, yes Baldor have them fitted to some of these motors, like the one you saw, they are easy to make, can be a lot less complicated than that one was, Baldor mounts it inside the Housing, very simple, just a single Brush holder, I have tried to find someone at Baldor to get some of them, but no luck yet

[Mmpie]

You don't need to change the Pulley with this motor, you will need the 5hp for your machining, this motor will do the 6,000 Rpm you need by just using your VFD programing

Hi Mactec. I have this lathe which I bought already retrofitted and stumbled across this thread. It just so happens that I will very soon have an all steel chuck and matching backplate to fit it and will be looking to increase my spindle speed from the current 3000 max rpm (current chucks max rating) to 5000 or 6000, so finding this was well timed. I have a similar but smaller 2.2kw AC induction motor that has 2840 rpm stamped on the plaque, like the one in this build has 3450. Now I assumed this was a max rpm rating for the motor and it is on a 1 to 1 pulley ratio the same as the build in this thread, so I was under the impression I would either need to change the pulley or use a different motor.

Given your advice in the quoted reply, I will be ok to just change max frequency in my VFD and you think the motor can handle the extra speed?

This is new territory for me so I'm not really sure about it.

[zmajmr]

Hi Mactec. I have this lathe which I bought already retrofitted and stumbled across this thread. It just so happens that I will very soon have an all steel chuck and matching backplate to fit it and will be looking to increase my spindle speed from the current 3000 max rpm (current chucks max rating) to 5000 or 6000, so finding this was well timed. I have a similar but smaller 2.2kw AC induction motor that has 2840 rpm stamped on the plaque, like the one in this build has 3450. Now I assumed this was a max rpm rating for the motor and it is on a 1 to 1 pulley ratio the same as the build in this thread, so I was under the impression I would either need to change the pulley or use a different motor.

Given your advice in the quoted reply, I will be ok to just change max frequency in my VFD and you think the motor can handle the extra speed?



This is new territory for me so I'm not really sure about it.

Hi, you can change max frequency, I aslo have motor which is rated to 2880 RPM, and I set frequency so I can get 4100 RPM, I can get even more but higher RPM give more vibration because I have air actuator on spindle for power chuck which is not dynamically balanced, so if it was I could use is on 5000 or 5500 RPM.

[Mmpie]

Hi, you can change max frequency, I aslo have motor which is rated to 2880 RPM, and I set frequency so I can get 4100 RPM, I can get even more but higher RPM give more vibration because I have air actuator on spindle for power chuck which is not dynamically balanced, so if it was I could use is on 5000 or 5500 RPM.

Thanks, that saves me a headache and a bit of cash then . Is there no problem at all running the motor above its max rating?

I have two more questions you may be able to answer. Is the max rpm rating of the spindle itself 4000rpm or 6000rpm? I have seen references to both speeds from different sources so I am not sure which one to believe, this is the standard 120 without power chuck.

Also, do you happen to know the dimensions of the spindle bore? I know the draw tube is 20.7mm ID but there is a larger ID at the back which I do not have accurate ID measuring tools to find it, only calipers.


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[zmajmr]

Thanks, that saves me a headache and a bit of cash then . Is there no problem at all running the motor above its max rating?

I have two more questions you may be able to answer. Is the max rpm rating of the spindle itself 4000rpm or 6000rpm? I have seen references to both speeds from different sources so I am not sure which one to believe, this is the standard 120 without power chuck.

Also, do you happen to know the dimensions of the spindle bore? I know the draw tube is 20.7mm ID but there is a larger ID at the back which I do not have accurate ID measuring tools to find it, only calipers.


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I have Emco 220 P, in manual say that max RPM is 6300 , so I went to see what will happen when I try to reach it and vibrations start to increase so I concluded it is better to limit it to 4100. Originaly motor was DC and 4.4 Kw and I use 1.5 KW AC 3 phase, so my motor is little weak but I can use it. Guy that was selling machine had 5 meter bar loader so for that kind of things you realy need big motor, I manage to use 1.5 kw but I saw some situations where more poewr would be good , at leas 3 KW.

Theoretically for use of VFD you should use motor which is constructed for use with VFD which have better insulation on wingdings for higher voltage but other then that if you are not gona use more then 6000 RPM there should be not problems , I rarely go under 1000 RPM so cooling is present all the time, I thought that maybe that will be problematic but it is not, from my experience there is no problems other then to have perfectly balance spindle for such high RPM.
On my 220 P bore is 25.5 mm, for 120 I do not know.

Also google for "vfd shaft current problems", you need to install some kind of protection otherwise your bearings will be damaged in motor.
This is my thread, you will find there my DIY shaft current protection https://www.cnczone.com/forums/verti...86042-cnc.html

[Mmpie]

I have Emco 220 P, in manual say that max RPM is 6300 , so I went to see what will happen when I try to reach it and vibrations start to increase so I concluded it is better to limit it to 4100. Originaly motor was DC and 4.4 Kw and I use 1.5 KW AC 3 phase, so my motor is little weak but I can use it. Guy that was selling machine had 5 meter bar loader so for that kind of things you realy need big motor, I manage to use 1.5 kw but I saw some situations where more poewr would be good , at leas 3 KW.

Theoretically for use of VFD you should use motor which is constructed for use with VFD which have better insulation on wingdings for higher voltage but other then that if you are not gona use more then 6000 RPM there should be not problems , I rarely go under 1000 RPM so cooling is present all the time, I thought that maybe that will be problematic but it is not, from my experience there is no problems other then to have perfectly balance spindle for such high RPM.
On my 220 P bore is 25.5 mm, for 120 I do not know.

Also google for "vfd shaft current problems", you need to install some kind of protection otherwise your bearings will be damaged in motor.
This is my thread, you will find there my DIY shaft current protection https://www.cnczone.com/forums/verti...86042-cnc.html

Thanks for the heads up, I will read through your thread this evening.

The 220 is the same iron I believe? What's the hardest material you think these things can turn? I've only used it on stainless so far, which it handles easily. I need to run some stuff in en19t (4140 or 4340 I think).

It's a great little lathe anyway, I love it. As said mine was already retrofit when I bought it, it has a no frills Chinese SZGH controller which seems to work well. The X, Z and spindle motors are all encoded, I use it for rigid tapping which it does very neatly. I have some changes I want to make, including a through coolant manifold and possibly automating the tailstock. I will share more info on it when I have chance.


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[zmajmr]

Thanks for the heads up, I will read through your thread this evening.

The 220 is the same iron I believe? What's the hardest material you think these things can turn? I've only used it on stainless so far, which it handles easily. I need to run some stuff in en19t (4140 or 4340 I think).

It's a great little lathe anyway, I love it. As said mine was already retrofit when I bought it, it has a no frills Chinese SZGH controller which seems to work well. The X, Z and spindle motors are all encoded, I use it for rigid tapping which it does very neatly. I have some changes I want to make, including a through coolant manifold and possibly automating the tailstock. I will share more info on it when I have chance. Yes it is great little machine, iron base is same as on 120 , probably head stock (bearing and spindle are different).


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I turned, stainless steel, titanium grade 5, aluminum, plastic and once hardened collet from collet chuck, so it can turn lot of different materials, you just need to have right tool. I also processed tail stock in my topic It is same iron , only headstock setup is different , there is few versions with different type of bearings.